Effects Of Different Usages Of Organic Animal Manure And Lime On Water Quality And Growth Of Tilapia In Ponds

The research last for eight months,including two stages.Water quality index were determined during stage l,which was from April to September in 2015.This experiment studied four different usage of chicken manure,consisting of a total of nine groups and three replicates for each group.It compared effects and application values of different usage of chicken manure in the process of tilapia.The results provided the theory basis for the development of new natural fertilizer for fish,and gave more data to form a reasonable fish aquaculture model.In stage 2,the objectives was to determine lime requirements of forty-five acid soils from Alabama using two methods,including traditional method?PB method?and titration method,and to evaluate the most suitable methods used in Alabama agricultural soils.The results showed that:1.The effects of chicken manure on water temperature,pH,total hardness,conductivity,TAN,NO2-N,total hardness and chl-a were not significantly different?p>0.05?in all groups.But total alkalinity,Ca-hardness,TP and SRP were significantly different in medium chicken manure groups?p<0.05?.Fish showed no significant difference in specific growth rates?0.43% day-1– 0.48% day-1?.There was significant difference in fish yield among the 12 ponds(1073.25–1260.75kg·ha^-1),with the mean of 1162.7±135.7 kg · ha^-1.The net production of fish in ponds was significantly different among the groups treated with no-manure(823.25 kg · ha^-1),low chicken manure(852.25 kg·ha^-1),medium chicken manure(1010kg·ha^-1)and high chicken manure(964 kg·ha^-1).2.The K-bicarbonate method provided precise estimates of lime requirement that were 9.6 to 27.2%?with the average of 12.9%?,greater than those obtained by the method currently recommended for use on pond soils.There was significant difference in net production of fish among the 6 ponds ranged from 631.7– 712.45 kg·ha^-1.It is likely that the K-bicarbonate method neutralizes more of the exchangeable acidity inpond bottom soil samples than does the current method recommended for pond bottom soils and thereby provides a more reliable estimate of lime requirement.Moreover,the method does not require a hazardous chemical,a mechanical shaker,or a pH meter as does the other method for pond lime requirement.The cost per analysis is also cheaper by the K-bicarbonate method than the method currently recommended for pond soils.In conclusion,to compare water quality index,net production under four does of chicken manure and two does of lime requirement,the results indicated that the medium chicken manure and K-bicarbonate method provided estimates of lime requirement were optimum so as to give consideration to the ecological benefit and economic benefit.